Fig. 3

Metabolic enzymes ASS1 and PYCR1 were upregulated in OSCC. A Abnormally expressed genes regulating metabolic enzymes in OSCC tissues (left) compared to adjacent normal tissues, or in KYSE150 under low-oxygen conditions (right) compared to normal conditions using RNA-seq data from our specimens. B Principal component analysis (PCA) score plots obtained from the metabolite profiles of KYSE150 cells under normal or oxygen-deprived conditions. C Volcano map of the altered metabolites under hypoxia. D Enriched metabolic pathway analysis of abnormal metabolites under hypoxia. E Schematic representation of glycolysis and the TCA cycle. The relative levels of representative metabolites are shown (n = 6). Abbreviations: G6P, glucose 6-phosphate; F6P, fructose 6-phosphate; OAA, oxalacetic acid; HK2, hexokinase2; PGK1, phosphoglycerate kinase 1; α-KG, alpha-ketoglutaric acid. F Schematic representation of arginine/proline/aspartate metabolism (n = 6). Abbreviations: Asp, aspartate; Arg, arginine; Asn, asparagine; Glu, glutamate; Pro, proline; Orn, ornithine. G Venn diagram for crossovers between metabolomic (left) and genomic (right) profiling. H, I Expression of ASS1 and PYCR1 at mRNA (H) and protein (I) levels in different OSCC cell lines or the Het-1A. J, K Expression of ASS1 and PYCR1 at mRNA (J) and protein (K) levels in time-course experiments under limited oxygen conditions. Student’s t test. NS: not signifcant, *p < 0.05, **p < 0.01, ***p < 0.001